Locomotive

ABSTRACT

Locomotive with a frame and at least one preferably diesel-electric drive unit, the frame being supported on at least two bearing sections, in the area of which the frame rests on wheel frames, and having at least one preferably dropped middle section extending between two bearing sections, wherein the middle section (B) substantially comprises two side parts ( 4, 4 ′) spaced apart from each other, each of which has a lower chord ( 6, 6 ′) and upper chord ( 5, 5 ′) running in longitudinal direction and at least one stay ( 7, 7′; 27, 27 ′) connecting the lower chord to the upper chord, and in that at least one drive unit ( 10, 10 ′) is arranged in the middle section (B) of the frame ( 2 ).

RELATED APPLICATION INFORMATION

This application is a continuation of PCT/AT2004/000224, filed Jun. 25, 2004 which claims priority from Austrian Patent Application No. A981/2003 filed Jun. 25, 2003 which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a locomotive, with a frame and at least one preferably diesel-electric drive unit, the frame having at least two bearing sections, in the area of which the frame rests on wheel frames, and at least one, preferably dropped, middle section extending between two bearing sections.

BACKGROUND

Rail vehicles for conveying passengers are already known, in which the dropping of the frame plate on the one hand serves to lower the rail vehicle's center of gravity, and in this way to prevent a derailment of the rail vehicle, and on the other hand allows low entrance heights. Locomotives are also known in which the frame middle section, as a rule developed in plate form, together with a known carriage structure forms the machine room, the drive units being arranged on the plate-form middle section of the frame. The middle section, arranged in a plane with the bearing sections of the frame, of the frame can be reinforced by means of a truss structure arranged under the middle section in plate form.

SUMMARY OF THE INVENTION

The object of the invention is to produce a space-saving structure for a locomotive, which at the same time allows better cooling of the machine room. An embodiment includes a locomotive with a frame and at least one preferably diesel electric drive unit, the frame being supported on at least two bearing sections, in the area of which the frame rests on wheel frames, and having at least one middle section extending between two bearing sections, wherein the middle section substantially comprises two side parts spaced apart from each other, each of which has a lower chord and upper chord running in longitudinal direction and at least one stay connecting the lower chord to the upper chord, and in that at least one drive unit is arranged in the middle section of the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and details of the invention are explained in more detail with reference to the figures represented in the drawing, in which

FIG. 1 schematically shows a side view of a frame according to the invention for a locomotive,

FIG. 2 a shows a section along line C from FIG. 1,

FIG. 2 b shows a section along line D from FIG. 1,

FIG. 2 c schematically shows a cross-section through the machine room with drive units arranged therein,

FIGS. 3 a and 4 a shows partial side views of a locomotive according to the invention,

FIGS. 3 b and 4 b shows partial top views of a locomotive according to the invention,

FIG. 5 shows a schematic representation of the operating principle of a cooling installation according to the invention,

FIG. 6 shows in perspective a conceptual drawing of a frame structure according to the invention with a partition wall and

FIG. 7 shows in perspective a conceptual drawing of a frame structure according to the invention with two drive units arranged one above the other.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention this is achieved in that the middle section substantially comprises two side parts spaced apart from each other, each of which has a lower chord and upper chord running in longitudinal direction and at least one stay connecting the lower chord to the upper chord, and in that at least one drive unit is arranged in the middle section of the frame, a preferred embodiment of the invention providing that the at least one drive unit is preferably secured exclusively to the stays connecting the upper chords to the lower chords.

Unlike the known plate-form middle sections, the middle section of the frame according to the invention is developed as a so-called bridge frame, which substantially comprises a total of four girders arranged in longitudinal direction of the rail vehicle. In each case two of these girders form a side part with an upper and a lower chord which are connected to each other by at least one stay. Such a structure allows a variable arrangement of the drive units—both in horizontal and in vertical direction—and also offers, as a result of the free spaces remaining between the lower and upper chords, the possibility of ventilating the machine room from below, for example with preferably adjustable air baffle plates, arranged on the underside of the machine room.

In order to allow unimpeded removal of the diesel-electric drive unit(s) upwards and downwards, it is provided according to a further version of the invention that securing brackets, for the fitting of the drive unit(s) are attached or can be attached to at least two stays lying opposite each other in relation to the longitudinal axis of the frame.

If, as is provided in a further embodiment of the invention, each middle section of a side part has precisely two stays connecting the lower chord to the upper chord, the securing points, preferably designed as brackets, are attached to these two stays. But the arrangement of additional vertical stays, to which the securing points are attached, is also possible.

As a rule the connection between the bearing sections and the middle section of the frame takes place at the stays, which can be aligned both vertically and at an angle. In order to improve the static properties of the frame structure according to the invention, according to a further embodiment of the invention cross-members can be arranged between the upper chords and/or the lower chords. A frame structure is thereby obtained in which the side parts, which have an upper chord, a lower chord and at least one stay, are connected to each other via cross-members, which is equivalent to a middle section of a frame which substantially comprises an upper and lower chord, both the upper and lower part in each case having side supports connected by cross-members, and in which the upper and lower parts are connected to each other via vertical stays.

A further version of the invention provides that the lower chords run below the bearing sections, i.e. the frame is dropped in the area of its middle section, whereby a lowering of the center of gravity is achieved.

A reduction in the space requirement is achieved if, according to a particularly preferred embodiment of the invention, the upper chords run above the bearing sections, favorably in the upper half, preferably in the top third, of the rail vehicle. In other words, this means that the distance between the lower chords and the upper chords should be sufficiently large that two drive units can be arranged one above the other in the machine room. Besides the huge saving in space, such an arrangement, together with the fact that the machine room is essentially bounded by the upper and lower chords, with a free space remaining between the two lower chords and the two upper chords in each case, creates a chimney effect. This natural ventilation of the machine room can be further supported by air baffle plates, arranged on the underside of the machine room and optionally adjustable.

The separation, hitherto generally resulting from the carriage structure, of the machine room from the switch room or driver's cab, can, in a rail vehicle according to the invention, simply result from the fact that the middle section is bounded by a wall at least at one end. It does not matter whether this wall is arranged between the stays and any cross-members present, or whether the stays and any cross-members present are part of this wall. The side- and end-walls bounding the machine room are designed such that the strength and installation requirements can be met, with simultaneously sufficient switching insulation. The two partition walls bounding the ends of the machine room increase the torsional stiffness of the locomotive frame over the vehicle's longitudinal axis and can carry switching and heat insulation as well as line installations to supply the drive units and optionally brackets to house any auxiliary sets that may be present. All the connections to the drive units are preferably realized in a vertical plane.

In order to ensure that the frame structure according to the invention for a rail vehicle withstands the enormous stresses to which it is exposed, a further embodiment of the invention provides that at least the upper chord of a side part projects over the middle section into a bearing section of the frame, it having proved advantageous if the upper chord projecting over the middle section into a bearing section is preferably connected in its end area to the bearing section via a stay. Besides the static improvements, such a version brings with it the advantage that the upper chord arranged in the area of the bearing section together with the stay connecting this upper chord to the bearing section can at the same time form the side part of the switch room.

A further preferred embodiment of the invention provides that the middle section is open at the bottom, it having proved advantageous if the bottom surface formed between the lower chords of the side parts of the middle section is more than 50%, preferably more than 80%, open. A particularly simple structure results if the bottom surface, apart from any cross-members present, is completely open, so that the welded frame structure is open above and below over its whole surface area in the area of the machine room, i.e. the machine room is bounded by only the side- and end-walls. According to a preferred embodiment, it is provided that the distance between at least two cross-members is at least 3 m, preferably 5 m. This means that the distance between at least two cross-members is greater than the longitudinal extent of the drive unit(s), with the result that the at least one drive unit can be arranged projecting below the lower chords in the frame of the locomotive.

A further embodiment variant of the invention provides that, in the case of a locomotive with a frame which is arranged on wheel frames and has an upper chord and a lower chord as well as at least two preferably diesel-electric drive units, at least two of these drive units are arranged one above the other. According to a further embodiment of the invention the lower drive unit can project below the lower chord and/or the upper drive unit can project above the upper chord. Besides a downward shift of the center of gravity, a particularly maintenance-friendly structure is thereby obtained.

For simple mounting of the drive unit(s) in the frame all the connections of a drive unit, which according to an embodiment of the invention comprises at least one combustion engine and one generator, preferably precisely one combustion engine with generator, can be developed in a vertical plane. Besides the combustion engine and the generator, the drive unit can additionally comprise one or more auxiliary sets. It has proved advantageous if the combustion engine, which according to a preferred embodiment of the invention is developed as a diesel engine, together with the generator, any auxiliary sets and line installations present and a mounting frame, forms a preassembled unit. The mounting frame should be developed for single- or double-vibration-insulated attachment of the drive unit(s) in the frame of the locomotive. The housing of cooling-air guides in the mounting frame is also possible.

The drive units arranged in the middle section of the frame between the side parts thus produce the energy necessary to power the locomotive, the electric motors being arranged in a manner known per se in the area of the bogie in the case of diesel-electric drives. However, a mechanical direct drive of the drive units arranged in the middle section of the frame to the wheels would also be possible.

Furthermore, particularly simple maintenance results, in the case of a rail vehicle with an machine room and a switch room in which the control and power devices installed in switch boxes are arranged, if at least one switch box is arranged movable across the longitudinal axis of the rail vehicle in such a manner that the switch box can be pushed or pulled out from a side wall of the switch room. The space freed up in the switch room by extracting the movable switch boxes can be used as a mounting passage, which in turn means a considerable space saving.

Moreover, a rail vehicle with a cooling installation which has at least two cooling units preferably arranged in the roof area, lying one behind the other in the direction of travel and able to be acted upon by a coolant flow, is to be provided.

The use of the air stream results in differences in cooling capacity, depending on the direction of travel, between the cooling unit situated at the front and at the back respectively in the direction of travel. According to the invention, this difference is to be compensated by a device for controlling the distribution of the coolant flow to the cooling units situated respectively at the front and back in direction of travel.

In the case of a rail vehicle according to the preamble which has air guides which conduct the air stream to the cooling units, a further embodiment of the invention provides that the air guides can be developed adjustable via adjusting devices, so that the cooling units preferably situated at the rear in direction of travel can be supported by an additional forced ventilation.

A basic idea of the invention is therefore to operate a cooling installation of a rail vehicle in such a manner that the device for controlling the distribution of the coolant flow and/or the air guides and/or fans provided in the case of cooling units, is or are adjusted differently depending on the state of movement, in particular the direction of travel, of the rail vehicle. The invention is based on the consideration to control the respective contributions of the front and the rear cooling units to the total cooling capacity, either by increasing the power of the preferably rear cooling unit by an additional forced ventilation or by dividing the coolant flow differently between the front or rear cooling units which differ in their power—depending on the direction of travel.

This can be achieved simply in that, when the rail vehicle is moving, the device for controlling the distribution of the coolant flow is set so that the coolant flow to the front cooling unit—seen in direction of travel—is greater than that to the rear cooling unit, the coolant flow to the cooling unit lying at the front in the direction of travel preferably being increased, and at the same time the coolant flow to the cooling unit lying at the rear in the direction of travel being reduced to the same extent. The same effect is achieved, according to a further embodiment of the invention, if when the rail vehicle is moving, the air guides and/or fans arranged in the cooling units are set so that the rear cooling unit—seen in the direction of travel—is acted upon by an increased air flow.

The frame 2 represented in FIG. 1 of a locomotive has two bearing sections A, A′ which rest on wheel frames 3 with wheels 17. The middle section B of the frame 2 extends between the two bearing sections A, A′. In the area of the middle section B, the frame 2 is dropped, improving the riding properties of the rail vehicle in particular on poor sections of track and on sharp curves, and making the sets more easily accessible. The side part 4 of the middle section B consists of a lower chord 6 and an upper chord 5 which are connected to each other by two stays 7. In the case of the embodiment shown, the stays 7 run, for static reasons, obliquely upwards from the base 6 to the upper chord 5. It would however also be possible to have the stays 7 running vertically or from the lower chord 6 obliquely inwards to the upper chord 5. The upper chords 5, 5′ and lower chords 6, 6′ bound the machine room 11 laterally at the top and bottom respectively. The free spaces which between them enclose the lower chords 6, 6′ and the upper chords 5, 5′ respectively can remain free for reasons of better ventilation. The ends of the middle section B which are formed by the stays 7 and any cross-members present, can for example be closed by structure-bearing walls 9, so that the machine room 11 is closed at the front and rear in the direction of travel, while the underside of the machine room 11 and the top side of the machine room 11 are completely open—apart from selective rain-protection devices for the drive units.

In the embodiment of the invention shown, the upper chord 5 of the side part 4 is longer than the lower chord 6 and projects over the middle section B into the bearing sections A, A′ of the frame 2, and is connected at its two end-areas via stays 18 to girders 19 of the bearing sections A, A′. These parts of the upper chord 5 that project into the bearing sections A, A′, together with the stays 18, form the side parts of the switch room 12. Buffers 16 are attached as usual to the ends of the frame 2.

FIG. 2 a shows that the bearing section A has two lateral girders 19 which are connected to each other via a cross-member 8. It is of course also possible to develop the frame 2 in the bearing section A in plate form.

FIG. 2 b shows that the two side parts 4, 4′, both in the area of their upper chord 5, 5′ and in the area of their lower chord 6, 6′, are connected to each other via cross-members 8 and in this way enclose the machine room 11.

FIG. 2 c shows in principle a cross-section through the machine room 11 with drive units 10, 10′ arranged therein. In order to be able to arrange the two drive units 10, 10′ one above the other, it is necessary for the upper chords 5, 5′ to be arranged in the upper half, preferably in the top third, of the height of the rail vehicle 1. The drive units 10, 10′ are fitted to the lower chords 6, 6′ or the upper chords 5, 5′ respectively of the frame 2 (not shown). The free space remaining at the side of or above the drive units 10, 10′ of the machine room 11 can for example be used for the installation of exhaust systems.

FIGS. 3 a and 3 b show the bearing section A situated at the front in the direction of travel F and part of the middle section B of the frame 2, in side view and top view respectively. Seen in direction of travel, the bearing section A lies in front of the middle section B. A wall 9 separates the machine room 11 from the switch room 12, which is laterally bound by a side wall 14. In the roof area of the carriage structure arranged over the bearing section A, a first cooling unit 15 of a cooling installation is arranged. A second cooling unit 15′ of the cooling installation is arranged in the roof area above the bearing section A arranged to the rear in the direction of travel (FIG. 4 a).

Above each of the cooling units 15, 15′ air guides 20 are arranged which for example can be developed as air baffle plates or as fans, so that in the case of the cooling unit 15 situated at the front in the direction of travel the air stream is directed essentially to the front end, whilst the introduction of the air stream in the case of the cooling unit 15′ situated at the rear in direction of travel F takes place chiefly via the air guide 20.

Furthermore, FIGS. 4 a and 4 b show that in the switch room 12 switch boxes 13 are arranged movable across the longitudinal direction of the rail vehicle. This brings with it on the one hand the advantage that maintenance or servicing on the switch boxes 13 can be carried out partly from outside, on the other hand such a structure offers the advantage of a huge saving of space, as the movement space needed for maintaining the fixed switch boxes 13′ during operation of the rail vehicle offers space for the inserted switch boxes 13.

FIG. 5 schematically represents the operating principle of a cooling installation according to the invention. The invention is based on the consideration that, as a result of using the air stream as a cooling medium for the cooling units, the cooling unit 15 lying at the front in direction of travel must make a much greater contribution to the total output of the cooling installation, as the cooling unit 15′ situated at the rear in the direction of travel is naturally acted upon by less air stream and generally also by the heated exhaust air from the machine room and exhaust system respectively. In order to match the respective contributions of the front and rear cooling units to the total output of the cooling installation corresponding to the power of the front and rear cooling units respectively, which depends on the cooling medium, there are in principle two possibilities.

On the one hand the coolant flow to the front and rear cooling units can be distributed at different respective strengths. For this purpose the cooling installation has a control device 22 which is connected to a valve 21 via a control line 24 and issues control signals to the valve 21. The valve 21 is connected on the input side to an engine 10 via a coolant line 23. There is a differential distribution, depending on the signal from the control device 22, of hot coolant flow, flowing from the engine 10 to the valve 21, to the cooling units 15, 15′. The hot coolant thus flows via the coolant line 23 to the respective cooling units 15, 15′, is cooled there and subsequently fed back to the engine 10, so that the coolant circuit closes. A basic idea of the invention is thus to feed a larger quantity of coolant flow to be cooled down to the front cooling unit 15 which, because of the greater quantity of cold air stream, is more powerful than the rear cooling unit 15′, and thus to relieve the less powerful rear cooling unit 15′. In this way both cooling units 15, 15′ are approximately equally loaded according to their power, thus in particular preventing the rear cooling unit 15′ from not being in a position to cool the hot coolant stream to the extent required.

On the other hand it is possible, with a constant coolant flow to both cooling units 15, 15′, to increase the power of the rear cooling unit 15′, by directing a greater quantity of air stream to the rear cooling unit 15′. For this purpose the cooling installation has air guides 20 which for example can be formed by air baffle plates or fans. These air guides 20 can be adjusted by means of an adjustment device 26 according to the operating state, in particular the direction of travel, of the rail vehicle, the adjustment device 26 being connected to the control device 22 via a control line 24. Thus, when for example the rail vehicle is moving, the cooling unit 15′ situated at the rear in direction of travel can be acted upon by more of the air stream by adjusting the air guides 20.

An optimal control of the cooling installation, i.e. an optimal distribution of the cooling power to be produced by the cooling installation to the two cooling units 15, 15′ according to their power can be achieved by a combination of both measures. In other words, on the one hand the cooling unit 15 situated at the front in direction of travel is acted upon by a greater coolant flow via the control device 22 and at the same time the cooling unit 15′ situated at the rear in direction of travel is acted upon by an increased air stream via the adjustable air guides 20.

Independently of the embodiment shown, it is an essential basic idea of the invention to control the contributions to be provided by the individual cooling units to the overall cooling capacity in such a way that this contribution is matched to the power of the individual cooling unit.

FIG. 6 shows a perspective view of a frame 2 according to the invention, from which it is clear that the dropped middle section of the frame, is separated from the front bearing section by a partition wall 9. Beside the angled stays 7, 7′, vertical stays 27, 27′ are additionally arranged between the upper chords 5, 5′ and the lower chords 6, 6′ of the two side parts 4, 4′.

As FIG. 7 shows, these vertical connecting stays 27, 27′ are used to install securing brackets 26, 26′. The drive units 10 in the middle section of the frame are fitted, via the mounting frame 28, to these securing brackets 26, 26′, which can be attached both to the angled stays 7, 7′, the vertical stays 27, 27′ and also the upper or lower chords. It has proved advantageous if all the connections attached to the drive units 10, 10′ are formed lying in one plane.

It goes without saying that the invention is not limited to the embodiments represented. A basic idea of the invention is to produce a frame structure for an engine frame of a locomotive which is essentially open above and below, and in this way, as well as providing good ventilation allows a particularly simple method of construction. Thus locomotives fitted with this frame according to the invention can be developed with only four axles, which means that the total weight of such a powerful locomotive is approximately 80 tons, whereas the locomotives of this performance class, usually fitted until now with six axles, corresponding to the state of the art, have a total weight of between 120 and 160 tons. This results in, amongst other things, a possible operating speed of at least 160 km/h for a locomotive according to the invention whereas the maximum operating speed for locomotives according to the state of the art was 120 km/h. 

1. Locomotive with a frame and at least one preferably diesel-electric drive unit, the frame being supported on at least two bearing sections, in the area of which the frame rests on wheel frames, and having at least one middle section extending between two bearing sections, wherein the middle section substantially comprises two side parts spaced apart from each other, each of which has a lower chord and upper chord running in longitudinal direction and at least one stay connecting the lower chord to the upper chord, and in that at least one drive unit is arranged in the middle section of the frame.
 2. Locomotive according to claim 1, wherein the middle section is dropped downward.
 3. Locomotive according to claim 1, wherein the at least one drive unit is secured to the stays connecting the upper chords to the lower chords.
 4. Locomotive according to claim 3, wherein the at least one drive unit is secured exclusively to the stays connecting the upper chords to the lower chords.
 5. Locomotive according to claim 1, wherein securing brackets for the fitting of the drive unit(s) are attached or can be attached to at least two stays lying opposite each other in relation to the longitudinal axis of the frame.
 6. Locomotive according to claim 1, wherein each middle section of a side part has precisely two stays connecting the lower chord to the upper chord.
 7. Locomotive according to claim 1, wherein cross-members are arranged between the upper chords and/or the lower chords.
 8. Locomotive according to claim 1, wherein the lower chords run below the bearing sections.
 9. Locomotive according to claim 1, wherein the upper chords run above the bearing sections.
 10. Locomotive according to claim 9, wherein the upper chords run in the upper half of the locomotive.
 11. Locomotive according to claim 10, wherein the upper chords run in the top third of the locomotive.
 12. Locomotive according to claim 1, wherein the middle section is bounded by a wall at least at one end.
 13. Locomotive according to claim 1, wherein at least the upper chord of a side part projects over the middle section into a bearing section of the frame.
 14. Locomotive according to claim 13, comprising a stay for connection of the bearing section to the upper chord.
 15. Locomotive according to claim 1, wherein the middle section is open at the bottom.
 16. Locomotive according to claim 15, wherein the bottom surface formed between the lower chords of the side parts of the middle section is more than 50% open.
 17. Locomotive according to claim 16, wherein the bottom surface is more than 80% open.
 18. Locomotive according to claim 16, wherein the bottom surface, except for any cross-members present, is completely open.
 19. Locomotive according to claim 5, wherein the distance between at least two cross-members arranged between the lower chords is at least 3 m.
 20. Locomotive according to claim 19, wherein the distance between at least two cross members is at least 5 m.
 21. Locomotive according to claim 1, wherein the at least one drive unit projects below the lower chords.
 22. Locomotive according to claim 1, wherein at least two drive units are arranged in the middle section of the frame and wherein two of these drive units are arranged one above the other.
 23. Locomotive according to claim 22, wherein the lower drive unit projects below the lower chord and/or the upper drive unit projects over the upper chord.
 24. Locomotive according to claim 1, wherein each drive unit comprises at least one combustion engine and one generator.
 25. Locomotive according to claim 24, wherein at least one drive unit additionally comprises one or more auxiliary sets.
 26. Locomotive according to claim 24, wherein each drive unit comprises precisely one combustion engine with generator.
 27. Locomotive according to claim 24, wherein the combustion engine is a diesel engine.
 28. Locomotive with a frame which is arranged on wheel frames and has an upper chord and a lower chord and at least two preferably diesel-electric drive units, wherein two of these drive units are arranged one above the other.
 29. Locomotive according to claim 28, wherein the lower drive unit projects below the lower chord and/or the upper drive unit projects over the upper chord.
 30. Locomotive according to claim 28, wherein each drive unit comprises at least one combustion engine and one generator.
 31. Locomotive according to claim 30, wherein at least one drive unit additionally comprises one or more auxiliary sets.
 32. Locomotive according to claim 30, wherein each drive unit comprises precisely one combustion engine with generator.
 33. Locomotive according to claim 30, wherein the combustion engine is a diesel engine.
 34. Locomotive, in particular diesel-electric locomotive, with an machine room and a switch room, in which the control and power devices installed in switch boxes are arranged, in particular according to claim 1, wherein at least one switch box is arranged movable across the longitudinal axis of the locomotive in such a manner that the switch box can be pushed or pulled out from a side wall of the switch room.
 35. Locomotive with a cooling installation which has at least two cooling units arranged in the roof area, lying one behind the other in direction of travel and able to be acted upon by a coolant flow, in particular according to claim 1, comprising a device for controlling the distribution of the coolant flow to the cooling unit situated respectively at the front and back, in direction of travel.
 36. Locomotive with a cooling installation which has at least two cooling units, arranged in the roof area, which lie one behind the other in direction of travel and are acted upon by a coolant flow, and air guides which conduct the air stream to the cooling units, in particular according to claim 1, wherein the air guides are developed adjustable via adjusting devices.
 37. Method for operating a cooling installation of a locomotive having at least two cooling units arranged on the roof area, which lie one behind the other in direction of travel and are acted upon by a coolant flow, and air guides which conduct the air stream to the cooling units and/or fans provided in the case of the cooling units, wherein a device for controlling the distribution of the coolant flow and/or the air guides and/or the fans is or are adjusted differently depending on the state of movement, in particular the direction of travel, of the locomotive.
 38. Method according to claim 37, wherein, when the locomotive is moving, the device for controlling the distribution of the coolant flow is set so that the coolant flow to the front cooling unit—seen in direction of travel—is greater than that to the rear cooling unit.
 39. Method according to claim 37, wherein, when the locomotive is moving, the air guides and/or fans arranged in the cooling units are set so that the rear cooling unit—seen in direction of travel—is acted upon by an increased air flow.
 40. Locomotive according to claim 12, wherein the wall is bounded by the stays connecting the upper chord to the lower chord and/or cross-members arranged between the upper chords and/or the lower chords.
 41. Locomotive, in particular diesel-electric locomotive, with an machine room and a switch room, in which the control and power devices installed in switch boxes are arranged, in particular according to claim 28 wherein at least one switch box is arranged movable across the longitudinal axis of the locomotive in such a manner that the switch box can be pushed or pulled out from a side wall of the switch room.
 42. Locomotive with a cooling installation which has at least two cooling units arranged in the roof area, lying one behind the other in direction of travel and able to be acted upon by a coolant flow, in particular according to claim 28, comprising a device for controlling the distribution of the coolant flow to the cooling unit situated respectively at the front and back, in direction of travel.
 43. Locomotive with a cooling installation which has at least two cooling units arranged in the roof area, lying one behind the other in direction of travel and able to be acted upon by a coolant flow, in particular according to claim 34, comprising a device for controlling the distribution of the coolant flow to the cooling unit situated respectively at the front and back, in direction of travel.
 44. Locomotive with a cooling installation which has at least two cooling units, arranged in the roof area, which lie one behind the other in direction of travel and are acted upon by a coolant flow, and air guides which conduct the air stream to the cooling units, in particular according to claim 28, wherein the air guides are developed adjustable via adjusting devices.
 45. Locomotive with a cooling installation which has at least two cooling units, arranged in the roof area, which lie one behind the other in direction of travel and are acted upon by a coolant flow, and air guides which conduct the air stream to the cooling units, in particular according to claim 34, wherein the air guides are developed adjustable via adjusting devices. 